Question

我动态创建了两个矩形，它们看起来像矩形，并处理了拖放事件，以便它们可以在Canvas中移动。稍后，当我按下UI上的某个按钮时，我想向画布中的每个Thumb动态添加一些字符串。有没有办法做到这一点。请帮忙。

Xaml：

 <uwpControls:LayoutTransformControl x:Name="MainLayoutControl" Grid.Row="4" Height="400" Width="600" HorizontalAlignment="Center"  VerticalAlignment="Center">
                    <Grid Grid.Row="4" x:Name="gridBarImagePanel"  BorderBrush="Black" 
                      BorderThickness="2">

                        <Image x:Name="BarCodeImage" 
                               RenderTransformOrigin="0.5,0.5"></Image>

                        <Canvas x:Name="cnvBarCodeImage">

                        </Canvas>
                    </Grid>
                </uwpControls:LayoutTransformControl>

后面的代码：

 private void CreateUIShapes(int numberOfWindows, List<Dimensions> dimensions)
        {
            Thumb th = null;
            for (int i = 0; i < numberOfWindows; i++)
            {
                th = new Thumb();
                th.Name = i.ToString();
                var item = dimensions[i];
                th.Width = item.Width;
                th.Height = item.Height;
                th.Foreground = new SolidColorBrush(Windows.UI.Colors.Transparent);
                th.BorderBrush = item.BorderColor;
                th.BorderThickness = new Thickness(3);
                th.DragDelta += (sender, e) => Th_DragDelta(sender, e, dimensions);
                th.DragCompleted += (sender, e) => Th_DragCompleted(sender, e, item.IsImageRotated);
                //RotateWindowsByAngle(90, th, dimensions, i);
                Canvas.SetLeft(th, item.left);
                Canvas.SetTop(th, item.Top);
                cnvBarCodeImage.Children.Add(th);
            }
        }

        private void BtnScan_Click(object sender, RoutedEventArgs e)
        {
            //How can I add some text to the Thumb controls at this point. There is no Children Property.

        }

Answer 1

由于Thumb不是ContentControl，因此您必须为其提供自定义ControlTemplate才能向其中添加文本。

这是一个简单的示例，展示了如何在代码中执行此操作：

using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Markup;
using System.Windows.Media;

namespace WpfApp4
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            var thumb = new Thumb
            {
                Width = 100, 
                Height = 50, 
                Background = new SolidColorBrush(Colors.Red), 
                Foreground = new SolidColorBrush(Colors.White), 
                Template = GetThumbTemplate("")
            };

            Canvas.SetLeft(thumb, 100);
            Canvas.SetTop(thumb, 100);

            RootCanvas.Children.Add(thumb);

            thumb.Template = GetThumbTemplate("Hello world!");
        }

        private ControlTemplate GetThumbTemplate(string text)
        {
            var template = "<ControlTemplate xmlns=\"http://schemas.microsoft.com/winfx/2006/xaml/presentation\" TargetType=\"Thumb\">" +
                           "<Border Background=\"{TemplateBinding Background}\">" +
                           "<TextBlock VerticalAlignment=\"Center\" HorizontalAlignment=\"Center\" Text=\"" + text + "\" />" +
                           "</Border>" +
                           "</ControlTemplate>";

            return XamlReader.Parse(template) as ControlTemplate;
        }
    }
}

创建Thumb时，我将Template设置为GetThumbTemplate并传入一个空字符串。 GetThumbTemplate用ControlTemplate和Border创建一个简单的TextBlock。然后，我解析XAML并将其返回。

将其添加到Canvas后，我使用Template方法更新Thumb的{{1}}，并传入要显示的字符串。

我希望这会有所帮助！

动态将项目添加到Thumb

1 个答案: